Improvement in electro-magnetic clocks



3 Sheets-Sheet1.

W. M. DAVIS.

, ELECTRO-MAGNETIC CLOCK. No. 176,740 Patented May 2,1876

(111mm lzweifion 3 She ets-Sheet 2.

W. M. DAVIS.

ELECTRQ-MAGNETIC CLQCK. N0.1.76,740. Patented May 2,1876

3 Sheets-Sheet'ta.

W. M. DAVIS. ELECTED-MAGNETIC CLOCK.

Patented May 2,1876.

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N.PETERS, FHOTO-LITHOGRAPHER. wASl-HNGTDN, D c.

UNITED STATES PATENT SEEIGE.

. WILLIAM M. DAVIS, OF CLEVELAND, OHIO.

IMPROVEMENT IN EL'ECTRO-MAGNET-IC CLOCKS.

Specification forming part of Letters Patent No. 176,740, dated May 2,1876; application filed April 19, 1875.

To all whom it may concern:

Be it known that I, WILLIAM M. DAVIS, of Cleveland, county of Cuyahogaand State of Ohio, have invented certain new and useful Improvements inElectro-Magnetic Clocks and declare the following to be a full, clear,and exact description thereof, reference being had to the drawingshereto annexed, which form part of this specification.

My invention relates to improvements in that class of electromagneticclocks wherein a primary or' regulating pendulum or clock is made topropel and regulate any required number of secondary clocks by means ofone or more secondary circuits.

The failure of electro magnetic clocks to come into more general'use isattributable, in a great measure, to the heretofore unavoidabledeterioration of electrical contact in the impinging surfaces of therheotome or other ourrent-director necessarily used in connection withsuch clocks. To obviate this difficulty is the main object of myinvention and discovery.

In immersing the impact-points in a liquid medium or im mergent anysuitable liquid may be employed; but I prefer kerosene, which I havefound, by continued experiment, will effectually preserve and maintainthese surfaces in that sensitive condition requisite for a prompt andreliable electric contact by the slight touch which the pendulum orchronometer-balance may be able to produce without sensibly affectingits time-keeping qualities.

Without discussing theories upon this question, whatever the difficultymay be which causes this deterioration of the contact-surface, theliquid immergent above mentioned successfully prevents its injuriousconsequences, either by preventing the production of the cause or byremoving the cause as fast as produced.

Whenever one or more extended series of secondary clocks, governed andactuated by one or more secondary circuits issuing from one or moresecondary batteries, are to be operated by a single primary pendulum, itis found necessary, in order to preserve the time keeping qualities ofsaid primary pendulum, to interpose between it and the said secondarycircuits one or more intermediate or secondary magnets, which may or maynot be provided with pendulums.

These secondary magnets I term auxiliary magnets, and their function isto open and close the secondary circuits by means of circuit-breakers.For this purpose the primary pendulum directs the electric flow from theprimary battery alternately through its own impelling magnet and one ofthe auxiliary magnets, while this latter magnet directs the more intensesecondary current or currents through one or more extended circuits ofsecondary clocks. By preference, the primary device and its auxiliariesare placed near together in a dry, warm 'chamber,'or other place wherethe changes of temperature are slow and small.

To attach a clock-movement to a primarypendulum tends to impair itstime-keeping qualities 5 therefore the movement is attached to asecondary pendulum, which may be driven by an auxiliary magnet, so as toenable the attendant to keep the entire system of clocks on true timesimply by observing and regulating the time of said auxiliary clock.

In the drawings, Figure 1 represents a primary pendulum with a detachedgravity-impellent and an oscillating mercurial current switch furnishedwith the necessary immergent-cups. Fig. 2 is a vertical longitudinalsection of said switch, and Fig. 3 a plan view of same. Fig. 4represents an auxiliary magnet as driving a pendulum and an auxiliaryrheotomeot'hard metal (preferably constructed of platinum) with asuitable immergent-cup, together with a pin scapewheel and long palletsfor driving any preferred clock-movement. The object of this auxiliarymagnet and rheotome, or other current'director operated by it, is torelieve the primary pendulum or other regulator from the extra workotherwise required when a number of secondary clocks are to be operatedand regulated by a single primary or regulating clock. Fig. 5 representsa secondary pendulum with its impelling-magnet and movable cock, by theto and-tro motioii of which the pendulum is kept swinging togetherwithits combined feed-hand and detent, operating the spur time-wheel ofasecondary clock. Fig. 6 is a view of the curved detent and the attachedfeed-hand separated from the rod.

- In Fig. 1, A is any suitable base for the attachment of the operativeparts of the primary pendulum. Bis the pendulum-bracket; and

O is a gimbalbar which rests upon it and clamps the upper ends of one,two, or more suspension-springs, d d. D is a divided clampbar forclasping the lower ends of springs 61 d and the upper end of thependulum-rod 0. E is-the pendulum-bob. F is an electro-magnet; and G itsarmature attached to the lifting-1ever H, which lever is secured, by aspring, to the adjustable bra cket I. it" are adjustable stop-posts tolimit the movement of lever-H.

This feature of my invention I regard as an improvement over theimpellent as shown in a former patent of the United States granted to meOctober 2st, 1871, No. 120,185. In connection with this feature of myinvention, I am also aware of a certain invention of V. Himmer, patentedJune 4, 1872, No.127,488. I regard the function of my adjustablestop-post as an improvement over the inventions just alluded to,inasmuch as by limiting the movement of the leverH a uniform result isob tained by the action of the magnet, whereas, by the stronger orweaker action of said magnet, the movement of lever B heretofore hasbeen correspondingly affected, thereby materially injuring thetime-keeping qualities of the mechanism.

By theadjustable character of my stop-posts it" I am enabled to governthe throw of the lever H exactly to its proper limits, and to control itwithin the same.

J is a horizontal impulse-arm to give moving impulse to the pendulum,and is secured to the bar D in the plane of the pendulums swing, butinclined a little upward, as hereinafter shown. K is an impelling-weightat tached. to the slender wire k, which wire has two loops near itsupper end, as shown in the drawings. K 70 together constitute a detachedgravity-im pulse. An attached gravity-impulse may be used in its steadupon this same hori zontal arm, provided its spring or pivot attachmentcoincides very closely with the center of motion of the pendulum. Whenthe pendulum is at rest that portion of the arm J where theimpulse-weight impinges should be on a level with the center of motionof the pendulum. j is a tappet-pin in the lower end of rods 6 foroperating the current-switch L.

The current-switch L is shown in detail in Figs. 2 and 3. M mayrepresent any suitable battery to act as a primary battery, and N aconductor from one of its poles to the central cup of the switch L. 0and P are two other conductors, which lead from opposite extiemities ofswitch L to the primary and auxiliary magnets, respectively, and fromthence to the other pole of the battery M.

In Figs. 2 and 3, a is the base to which the ease of current-switch L isattached. This case L is to hold the operative parts of thecurrent-switch, including a suitable cement, 0, as a support forcontaining-tubes, as will hereinafter more fully appear. The middleportion of this case is lower than the two end portions thereof, and isrepresented by the dot ted lines 1), Fig.2. R is a rock-shaft to whichare secured the are S, impulsehorns Y Y and the platinum plate W, theshaft being held in position by the double-kneed brackets T T. N, 0, andP are continuations of the same conductors shown in Fig. 1 by the sameletters. Q is the central glass tube, held in position by cement c, andis filled with niercury, to secure a constant and reliable electricalconnection between the conductor N and the rock-shaft It, by means of asubmerged platinum plate, X, (which is attached to wire N,) and theoscillating plat-e WV, upon the rockshaft It. g y y g are fourstop-posts, to limit the movement of the rock-shaft R. m m are siphonshaped tubes, to hold the mercury which is to form electrical contactswith are S. Z Z are two immergent-cu is, which surround, respectively,the longer ends of the tubes in m which are designed to hold the liquidimmergent, so as to cover the surfaces of the mercury contained in thosetubes. It is this contained liquid which preserves these metallicsurfaces in that sensitive and desired condition to electric contactswhich is so essential to that prompt and certain electrical connectionrequired for successful operation of electric clocks. This liquid(preferably kerosene) should be a s0-called non-conducting medium, butone which will, at the same time, preserve unimpaired the active andconducting power of the contact-surfaces of the current-director towhich it is applied, and which it surrounds. The upper surface of thisliquid is shown at lines t L, Fig. 2. n a are wastepipes, to draw offthe liquid immergent from cups Z Z whenever it may be necessary. Theliquid known as kerosene or coal-oil, also other hydrocarbons, have beenused for the purpose justmentioned with satisfactory results. Moreover,many other liquids have been used, but none of them, so far as I amaware, have as yet been subjected to that long and crucial. test theseliquids (hydrocarbon) have been.

The mercury may be placed in the bottom of immergent-cup Z, and thekerosene or other suitable liquid poured over it with good effect; butthe form of vessel herein described, or some equivalent thereof, ispreferred, because the liquid immergent with the deflagrated mercury canthen be drawn off and new liquid supplied without disturbing the surfaceof the mercury in the least.

U U are two reservoirs for mercury, which are bedded in cement 0, andwhich communicate with tubes m m to furnish them with a constant supplyof mercury, inasmuch as a minute portion of mercury is defiagrated bythe electric spark at every break of either circuit. The mercury in thereservoir U U and tubes at on) also serves to secure electricalconnection between the reservoir U U and the mercury in the tubes m on,respectively. h h are platinum plates at or near the bottom of saidreservoir, to secure constant electrical connection between thecontained mercury and the conductors 0 P. The are S is made sufficientlylong, so that its point 8, by the rocking shaft R, is immersed inmercury m before the point s is withdrawn from themercury in m -,-andvice "ersa. By this means the defla gratin g'effect of the electricspark is materially diminished.

In Fig. 4, which represents the auxiliary magnet and its adjuncts, theletters A to K, inclusive, refer to parts of the auxiliary mag net andits pendulum, corresponding to parts of the primary pendulum in Fig. 1,which are indicated by similar letters. This pendulum is propelled bythe'elastic force of the spring K, attached by the lever H to thearmature of the auxiliary magnet F. L is the rheotome with itsimmergent-cup Z which .is so arranged as to make and break a secondarycircuit, which includes the magnets of a numher of secondary clocks tobe opera-ted by the 7 primary pendulum. P P are continuations ofconductor P, as shown in Fig.1. 1 is a pin scape-wheel for driving anysuitable clockmovement, if desired. 2 and 3 are impellingpalletsattached to the rod 0, to give motion to the wheel.

Rheotome L is constituted as follows: E

is a rock-shaft,'to which are attached the.

pendant vibrating contact-point S and the impulse-horns Y Y Therock-shaft It is put into electrical connection with conductor 1? (whichissues from a secondary battery) by anyof the ordinary methods. m m aretwo stationary contact-surfaces, formed of any suitable metal, and soplaced and insulated from shaft R and from each other that each mayreceive contacts from the lower end of movable point S when that pointis actuated by rod 6 To the upper end of strip 122. is attached aconductor, N, including the magnets of a n umber of secondary clocks,and connected with the other pole of the aforesaid battery. Another likewire may be attached to the strip m and so forming another circuit ofsecondary clocks from the same battery, may run another like number ofsecondary clocks. Z is an immergent-cup of suitable form, so placed thatits containedliquid immergent will completely surround thecontact-points m m S so that no part of the cup will interfere withtheir proper performances.

I do not confinemyself, however, to this particular arrangement ofparts, as the cup may be placed at a distance from the contactpoints andthe contained liquid be automati-- cally supplied to them at intervalsof more orless frequency, especially if the contacts are made by thefriction of the points 5 or the fixed point may be placed outside of thecup, and the movable point so arranged as to dip into the liquid in theact of breaking the electric circuit, In both cases the advantage of theliquid is secured without making the contacts beneath its surface. Thisrheotome may be operated directly by the armature of the magnet withoutthe intervention of a secondary pendulum, unless it be desired tooperate the clock-movement by said pendulum,-so

{that the entire system of clocks may be kept" on time by observing andregulating the time iof this one. In Fig. 5 the letters A to F inclusiveand E refer to parts of the secondary pendulum corresponding to those ofthe priimary pendulum in Fig. 1, which are indicated ;by similarletters. G is -the armature of the :magnet F and at the same timeconstitutes the movable cock for driving the pendulum le 7 is a curvedmetallic plate secured to the .rod 6 at the required height, and isdesigned to perform the functions of a detent. Sis a feed-hand in theform of a thin metallic spring ,secured by one end to the upper side ofplate {7. The free end of said spring is bent down-. ward through asuitable opening near the center of the plate, as seen in Fig. 6. 9 is aspur time-wheel of not less than three teeth,

and is designed to give motion to the second-' 10 and 11 are two teethof said ary clock. :wheel. 2 is a click, to prevent a backward motion ofthe wheel 9. 13 is a bracket, to support the outer end of the shaft. Ina working machine the spur-wheel and its adjuncts, in order to drive theclock, are placed in front of the pendulum and in connection with aclock, instead of behind it, as shown in the drawings.

Operation: The combined operation of the primary pendulum and currentswitch L, Figs. 1, 2, and 3, and their effect on the auxiliary magnetand its adjuncts, is as follows: The batteries being charged and all thenecessary connections made, the primary pendulum is put in motionbyhand. As this pendulum swings to and fro, it tilts the are S alternatelyto right and left by the action of pin j in the horns Y Y By this actionof the are S the electric current which flows from the primary batteryM, through wire N, to the are S .is directed alternately through theprimary magnet F and auxiliary magnet F thence to the other pole of theprimary battery.

The effect of these changes in the directionof the current on theprimary pendulum may be briefly stated as follows; As represented in thedrawing, the pendulum is at the right extremity of its swing, havingtilted the are S to the right, thus closing the circuit through cup Zand breaking it in cup Z. By this action of are S the entire current isdirected I through wire Paud auxiliary magnet B, Fig.-

4, while magnet F remains uncharged. Just before this movement of are Stook place,

however, arm J had reached the upper end of v its loop in wire it, andhad lifted that wire quietly fromlever H, after which said leverdroppedto its lowest point upon the stop-post i, because the magnet Fwas then discharged.

1 As the pendulum E c swings to the left, the wire K descends on the armJ, thus imparting motion to the pendulum until the upper loop in thewire Kreaches the lever H, when the arm J is relieved from its furtherpressure. \lVhen this relief shall have fully occurred are S will betilted to the left, and magnet F, being thereby charged, lifts wire K toits high.

est point, until the lever H impinges against the stop-post t, and holdsit firmly there, until the pendulum nears the right-hand limit of itsswing again, when it will be taken gent 1y up by the arm Jjust beforethe magnet F is discharged, to be ready to give. the pendulum anotherimpulse. These impulses recurring at the properintervals of time, andbeing constant in amount, owing, as heretofore stated, to my arrangementof adjustable posts it, produce a uniform amplitude of swinging of thependulum. As rod E swings to the right the pin j strikes the horn Y andthrusts the end 8 of the are S into mercury 122 before the points of theare S is withdrawn from the mercury in m, as before shown.

By this arrangement of parts the electric current is at no time entirelyarrested, but begins to flow through the mercury in m before it ceasesto flow through the mercury in m; hence the name current-switch has beengiven to this portion of my device.

While the are S remains in the position shown in Fig. 1 the electriccurrent flows through the magnet F Fig. 4, holding up the lever H, thusgiving an impulse to the pendulum E 6 During this interval the lever E,Fig. 1, is resting on its lower stop-post, and will remain there untilthe wire K has been deposited upon it by the downward swing of the armJ, after which, by the return swing of rod 0, magnet F will berecharged, lifting the weight K to its highest point, preparatory togiving the pendulum another impulse.

This current-switch may be used in connection with a clock which is runby a weight or spring. In this way it may be actuated by theelock-movement instead of the pendulum, as here shown.

The operation of the auxiliary magnet and its adjuncts is as follows: Inorder that the pendul u m,which is driven by this auxiliary magnet,

may perform its functions properly, it must first be so adjusted thatits natural beat shall coincide closely in time with those of itsregulator. When so adjusted, and the necessary connections are made withthe primary clock and its battery, the operation proceeds as follows:When the magnet is charged by the action of the primary clock, thearmature G is drawn to its poles and firmly held there until the tensionthus produced in the spii 1g K is expended in giving motion to thependulum. When this pendulum has reached the normal amplitude of itsswing, and begins to move again to the left, the point of pallet 3strikes the upper. side of pin 4 and presses it downwardjust as point 2recedes from the upper side of pin 5. 0n the return swing of thependulum the point of the pallet 2 strikes the under -side of pin 5, andpresses it upward just as pallet 3 is withdrawn from the pins opposite,while click or pawl 6 prevents any backward movement of the wheel. Bythe successive impulses thus given to it this wheel is caused to driveany desired clock-movement to serve the purposes of a secondary clock.

In a working machine the pin-wheel and pallets are placed before thependulum, and in connection with a clock-movement, instead of behind it,as shown in the drawings. While this pendulum is swinging to and fro theoperation of .the rheotome L will obviously be as follows: As rod 0swings to the left and strikes the horn Y point S impinges and restsagainst the strip m thus closing the secondary circuit through the WiresP N, and secondary magnetF Fig. 5. As rod 6 swings to the left again,and strikes the other horn of the rock-shaft R, this circuit will bebroken. The making and breaking of the secondary circuit by theoperation of the magnet G keeps, up a corresponding motion in each ofthe secondary clocks connected with this secondary circuit, thusinsuring their perfect concert of action.

It will be seen that these contacts are made by percussion. By a slightchange in the form of slips m m the contacts may be made by friction.

The operation of each of the secondary clocks in Fig. 5 will be asfollows: This secondary pendulum E 6 like others, must be so adjustedthat its natural beats will coincide closely with those of itsregulator. When so adjusted, and the necessary connections are madebetween its magnet, the secondary battery, and the rheotome L the actionof the several parts will be as follows: The magnet F being charged, thearmature G is drawn to its poles, which gives an impulse to the pendulumE e to swing to the left. Just as the pendulum reaches the limit of itsleftward swing, the armature G is released from the magnet, thusallowing both the pendulum and armature to swing to the right again. Asthe pendulum nears the right extremity of its swing, the armature isattracted to the magnet again, thus giving a new and increased impulseto the pendulum to swing to the left. These impulses being repeated atthe proper intervals of time soon give to the pendulum its requiredamplitude of swing, with power sufficient to drive theclock. Thisoperation will now be described. As the pendulum swings to the right,feed-hand 8 slips over the end of tooth l0, and falls down behind it,and as the pendulum swings to the left again, the feed-hand catchestooth 10, and pushes it up in front of it through the opening in plate7, when,-by the onward swing of the pendulum, this tooth is immediatelywithdrawn again from the said opening just as the next tooth reaches theunder side of plate 7, and

is there detained by it from further motion. At this point of theoperation tooth ll falls in front of pawl 12, which prevents anybackward motion of the wheel, and no forward motion can take place, asthe detent never swings entirely beyond the teeth of the wheel. By thisarrangement of the parts one tooth, and one only, can be moved forwardby each return swing of the pendulum.

What I claim is ment limited by the stop-bars z a, substantially as andfor the purpose described.

4. The combination of the primary magnet F, primary pendulum E e,current-switch L, secondary or auxiliary magnet F, with or without apendulum, E 6 auxiliary rheotome L secondary or auxiliary battery, andone, two, or more clock-movements, constructed and operatedsubstantially as shown and described.

WILLIAM M. DAVIS. Witnesses:

J. H. HEssrN,

G. W. STOGKLY.

